rear tires hop w/ tranz brake

[plum360415]

I have 75 Duster Indy 415,Cal-tracs,727w/ 5200 stall, about 3200# with driver. Have cal-tracs adj.w/1turn pre load. The car bites hard when the tranz brake is used---any rpm from 3k to 5k then looses tracsoin then bites again, does'nt matter if on the street or the track. I will leave black marks when the tranz-brake is released then real faint black marks(about 6 inces. then dark black marks. best 60 ft so far is 1.72 the car runs best of 1/4 in 11.21@124. The speed should be making the et in the hi 10s---right? Any input of what i'm not doing or what I should do? Thanks in adv.

 

[OUTLAW]

Well I'm no Caltrak specialist and I know most everyone will tell you to add a nother turn of pre load to them. But my experience with mopar suspension and getting them to launch says back the pre-load off until you are about 1 turn loose of neutral (1 turn from touching ). Every mopar I have ever raced needs a bit of room to allow the suspension to work. I call it "shock ' room. This will allow the suspension to start the rotation freely and then loads the suspension. While loaded the susension wants to unload (naturally) and with it tight there is no room to work so the tires then become the weak link so they break and grab etc


just my opinion

 

[onehellofadart]

I believe Outlaw is correct a full turn on the caltracs may be too much.

Also what is your tire pressure? What are you running for shocks?
Are your shocks adjustable?
I adjusted my Cal Tracs to hell and back till I finally started to play with air pressure and shock adjustments. Now no problem.

I don't have the power to turn 10's but I would spin just the same. Mine are adjusted just to touch the leafs and I'm in the top hole.
Started tire pressure at 20lbs and found sweet spot at 16lbs on drivers side and 15lbs on passenger side.